The invention is in the field of couplings which may be used on agricultural, construction or other equipment.
There is a need for couplings to communicate hydraulic fluid to and from tractor mounted hydraulic power sources. There is also a need to communicate hydraulic fluid to and from agricultural or construction implements. A directional valve downstream from the power source controls the direction of the fluid in the hydraulic lines and, hence, the direction of the implement. Interposed between the directional valve and the load are a manifold and shut off valves. Typically, female coupling halves are carried in the manifold and male coupling halves are affixed to hydraulic lines leading to and from the implement. Use of a manifold is optional and female coupling halves may be mounted directly on the tractor or other device. It is therefore necessary to provide a coupling having valves which remain open and stable as the flow direction is reversed and which will not result in the valves closing upon reversal of flow and unintentionally and undesirably preventing flow (i.e., flow checking).
When an implement is disconnected (uncoupled) from the manifold, it is desirable to maintain implement in a safe position by trapping fluid under pressure in the hydraulic lines between the male half of the coupling and the implement. The trapped fluid enables safe positioning of the implement until its next use. Sunshine and/or ambient heating further raise the pressure in the hydraulic lines leading to the implement making it difficult to connect (couple) the male coupling half into the female coupling half of the manifold for continued operation of the implement. When an implement is uncoupled from the manifold, fluid is also trapped between the female half of the coupling and a shut off valve interposed between the manifold and the directional control valve. Sunshine and/or ambient heating tend to increase the pressure of hydraulic fluid in the hydraulic lines and in the coupling making it difficult to couple the halves of the coupling together.
In some applications, shut off valves are used to intentionally trap fluid between the shut off valve and the load when the load remains connected so as to maintain the safe positioning of the implement. The shutoff valves or their functional equivalent may be integral with the directional valve. In this instance too, sunshine and/or ambient heating tend to increase the pressure of hydraulic fluid in the hydraulic lines and in the coupling.
It is desirable to provide a coupling which makes disconnection of the coupling halves easier and reduces or eliminates spillage.
It is desirable to provide a coupling which enables the male half of the coupling to close prior to disconnection of the coupling so as to minimize spillage and so as to trap pressure in the male coupling half and the hydraulic line leading to the implement.
It is desirable that the coupling halves be capable of connection under pressure, that is, with pressure applied to both halves of the coupling. It is further desirable that pressure be reduced or eliminated in the female half of the coupling to facilitate coupling. U.S. Pat. No. 5,937,899 to Zeiber discloses a female cartridge which is retained within a manifold. Axial and radial vent valves are disclosed. The ""899 patent provides a male half of the coupling which pushes the inner body of the pressurized female half of the coupling (which includes a pressurized chamber between a piston and a relief valve positioning member) causing the positioning member to be displaced in a leftward or rearward direction which causes the venting of the female member. The male half of the coupling pulls the inner body of the female half of the coupling rightwardly or forwardly which causes the venting of the female member. The venting occurs when the male and female halves of the coupling are connected or disconnected.
U.S. Pat. No. 5,709,243 to Wells et al. discloses a low spill female coupling. A valve having an enlarged head is adapted to receive a male valve from the male half of the coupling such that the valves remain closed until respective parts thereof are brought into contact with each other so as to minimize spillage.
U.S. Pat. No. 6,095,190 to Wilcox et al. discloses a female coupling half having internal pressure relief. The female half has three valves: a main valve, a relief valve and a sliding sleeve valve. The relief valve is a ball and seats against an elastomeric seal mounted on the back side of the main valve. A push pin having flat edges operates the relief valve.
U.S. Pat. No. 4,077,433 to Maldavs illustrates a piston valve arrangement with a passageway through the valve to assist in assuring that the male ball valve remains open in high flow conditions from the male to the female. U.S. Pat. No. 4,881,573 to Durant illustrates a coupler having two poppet valves. The first poppet engages a ball check valve formed in the male coupling and the second poppet is actuated by a manually operated cam. A passageway exists in the piston to allow fluid to be vented or to pressurize the female valve.
U.S. Pat. No. 4,598,896 to Maldavs illustrates a coupler having a spool and a port within the spool. An annular seal is fixedly positioned about the port in the spool. The spool is slidable with respect to the seal which enables pressure to be relieved in the female during coupling and uncoupling with the male. U.S. Pat. No. 4,303,098 to Shindelar discloses a coupler having a female half which includes a female valve having an elongated stem for engaging the male half. The female half of the coupling is vented by a pivotable cam which moves the inner member of the female half to release its locking means and then opens a poppet valve to open the outlet port.
U.S. Pat. No. 4,249,572 to Shindelar et al. discloses a female half which is self-relieving. The female half includes dual poppet valves which are linked together. One of the poppet valves vents the female half of the coupling when the male and female valves are disengaged and uncoupled.
U.S. Pat. No. 5,730,185 to Wilkins et al. discloses a coupling wherein certain positions of the adaptor allow the venting of the dispenser half and the receptacle half. Venting is prohibited by the movement of seals relative to ports and passageways.
U.S. Pat. No. 3,730,221 to Vik provides an exterior vent valve.
U.S. Pat. No. 4,745,948 to Wilcox et al. discloses a coupling device which utilizes locking detents which lock a stem against the male valve which prevents reverse flow checking.
A female coupling half for use with a male coupling half is disclosed. The male coupling half includes a male valve and a male body. The female coupling half includes an outer body, a housing, an inner body and a female valve. The inner body is slidingly movable with respect to the housing between a first position and a second relief position. The housing resides partially within the outer body forming an annular passageway therebetween.
Another embodiment of the invention employs a female coupling half which includes a cartridge retained within a manifold. In this embodiment, flow through the female coupler half is radially directed to a port in the manifold.
In both embodiments, an inner body adaptor is affixed to the inner body. A dump valve body and lock piston slidingly engage the inner body adaptor. A dump valve (relief valve) is seated against the dump valve body. A valve lock shaft is slidingly engageable within the lock piston. During connection of the coupling halves under pressure, the female valve is affixed to the valve lock shaft and movable therewith between a first position and a relief position. The male body engages the inner body member and the male valve engages the female valve urging them from their first positions to other positions upon insertion of the male coupling half into the female coupling half.
During connection of the coupling halves under pressure, the dump valve moves with the inner body member actuating the dump valve relieving pressure within the female coupler half. Before coupling and during venting, the valve lock shaft and the lock piston are releaseably secured to one another. As coupling begins and venting occurs the male body urges the inner body of the female coupling half leftwardly and carries the valve dump body, the valve lock piston, the sliding sleeve, the retainer and the valve lock shaft with it. Detents carried by the inner body engage the male body and the inner body member is urged leftwardly. At this time the male valve remains closed and has not yet engaged the female valve. Further, at this time the male body has not yet engaged the retainer of the female coupling half.
Coupling continues further by urging the male half of the coupling further into the female half of the coupling such that the body of the male first engages the retainer followed by the male valve engaging the female valve. Since the body of the male engages the retainer slightly in time before the male valve engages the female valve the retainer and seal carried by the retainer separate slightly from the lip of the female valve. This enables subsequent repressurization of the female coupler to open the male valve and to further open the female valve. As the coupling progresses, the female valve and valve lock shaft are driven rearwardly causing detents carried in the lock piston to exit a circumferential recess in the valve lock shaft. A lock sleeve is positioned against a snap ring secured in the sliding sleeve by a spring operable between a shoulder on the sliding sleeve and the lock sleeve. As the retainer is engaged by the male body member, the sliding sleeve of the female coupler half is urged leftwardly which, in turn, urges the lock sleeve leftwardly through the spring operable between the lock sleeve and the sliding sleeve. When the coupling is disconnected, the lock sleeve is spaced apart from the detents carried in the lock piston. This allows for the detents to be displaced from the recess in the valve lock shaft before the lock sleeve drives the detents and the lock piston leftwardly. Therefore, as the male body engages the retainer followed by the the male valve engaging the female valve, the sliding sleeve, the valve lock shaft and the lock sleeve all begin to move leftwardly while the coupling is vented. The movement of the lock piston is delayed, however, until the lock sleeve drives it leftwardly.
Next, the force on the male coupling half (i.e., the force exerted by a human hand) is removed and the coupling is fully connected but the male valve remains closed until pressure is applied to the female coupling half. At this time the female valve is slightly open. As pressurization of the female coupling half begins pressure equalization of the male and female halves occurs. The male and female valves shift rightwardly until the valve lock shaft moves sufficiently rightwardly that the detents carried by the lock piston are urged radially inwardly to engage a circumferential recess in the valve lock shaft. The lock sleeve secures the detents in the recess while the coupling is engaged ensuring that the male and female valves in the coupling remain open during use of the coupling. This prevents unwanted reverse flow checking.
To disconnect the pressurized coupling, the male coupling half is urged leftwardly into the female coupling half to vent the female half of the coupling. As the male coupling half is urged leftwardly, pressure in the coupling urges the coupling halves apart and acts upon the interface between the body of the male coupling half and the inner body member locking the detents carried by the inner body member into engagement with the land on the locking sleeve. Once pressure is vented from the coupling, the male body no longer applies force on the detents carried by the inner body member allowing them to move radially inwardly and out of frictional engagement with the land on the lock sleeve. A spring is operable between the vent valve and the valve lock shaft. The spring is compressed as the vent valve engages the housing or, in another embodiment, the manifold body. As pressure is relieved by the vent valve from the coupled condition, pressure is first reduced in the piston chamber formed by the lock piston, the valve dump body and the inner body adaptor. The piston chamber is separated from the remainder of the female coupling half by a resistance in the form of an annular passageway about the stem of the vent valve and the inside diameter of the valve lock shaft. An additional resistance in the form of a vent passageway is formed in the vent lock shaft. These resistances isolate the chamber from the fluid pressure external to the valve lock shaft. In particular, a seal between the lock piston and the inner body adaptor and a seal between the valve lock shaft and the lock piston experience relatively lower pressure as the chamber is vented as compared to seals which reside externally to the valve lock shaft. Specifically, a seal which operates between the valve lock shaft and the lock piston and a seal which operates between the sliding sleeve and the lock piston experience relatively high pressure. The differential pressure on the aforementioned seals results in shuttling the valve lock shaft leftwardly enabling the male and female valves to seat prior to disconnection. At this time the male valve engages the female valve such that no space is created therebetween so as to minimize fluid spillage on disconnection. The coupling halves are then pulled apart and separated with pressure trapped within the male coupling half so as to enable the safe positioning of an implement.
If the male and female coupling halves are not pressurized the male coupling half is inserted into the female coupling half urging the inner body member leftwardly. The inner body adaptor, the valve dump body, and the relief valve are all moved leftwardly under the urging of the male body against the inner body member of the female valve. The male valve engages the female valve as coupling progresses. The relief valve engages the bore of the manifold and the spring operable between the relief valve and the valve lock shaft overcomes the spring operable between the male valve and the canister in the male valve opening the male valve. The female valve opens simultaneously with the opening of the male valve.
The coupling may be easily separated if it is not under pressure as the coupling halves are not pressure locked together. Separation in the absence of pressure is accomplished by pulling the male body member and valve away from the female half of the coupling. A spring operable between the inner body adapter and the sliding sleeve urges the sliding sleeve and retainer rightwardly. As the male valve is withdrawn from the female valve, a spring operable between the canister of the male coupling half and the male seal retainer urge the male valve to its closed position.
It is an object of the present invention to provide a coupling which is a low spill coupling on connection and disconnection.
It is a further object of the present invention to provide a coupling which may be easily connected with pressure applied within the female coupling half and/or the male coupling half.
It is a further object of the present invention to provide a coupling having a female coupling half which is manifold mounted.
It is a further object of the present invention to provide a coupling which locks the valves of the male and female coupling halves in the open position and which prevents reverse flow checking of the male and female valves in the event that the direction of the flow is reversed or changes.
It is a further object of the present invention to provide a coupling which opens and locks the male and female valves of the coupling halves in the open position by applying pressure to the female half of the coupling once it is coupled together with the male.
It is a further object of the present invention to provide a coupling which enables the male coupling half to trap pressure therein upon disconnection of the coupling.
These and other objects of the invention will be better understood when the Brief Description of the Drawings, Description of the Invention and claims set forth below are read.